Jeff Longtin on mon 10 jan 11
Hey May,
Roughly speaking a 24 ounce yogurt container holds enough plaster powder to
cast a 50 cubic inch object. (Once mixed with the necessary amount of
water.)
This unit is the main unit I use to judge how much plaster I need for any
one casting.
Rather than measure out plaster and water for each casting I realized it
would be simpler to create my own measuring cup and corresponding "graduate=
d
cylinder".
I filled a 24 oz. container with plaster powder then I calculated how much
water was needed. I then created a graduated cylinder out of an empty 2
litre pop bottle, with the top cut off, in increments equal to each 24 oun=
ce
container.
A 16 ounce yogurt container holds enough plaster powder to cast an object
25-30 cubic inches in volume. (roughly speaking)
I mix my pottery plaster with a 70 parts water to 100 parts plaster powder
ratio, btw.
take care
Jeff Longtin
Minneapolis
In a message dated 1/10/2011 11:24:09 A.M. Central Standard Time,
claywedgie@GMAIL.COM writes:
Hello all;
I was trying to be a smarty pants and calculate the volume of a
cylinder to figure out how much plaster to pour for a mould.
I have radius =3D 14 cm. Pi =3D 3.14 Height =3D 15 cm.
14 x 14 x 3.14 x 15 =3D 9231
Is that ml / cc for the volume unit?
N.B. This is only for the cylinder, I did not factor in the hollow
part (displacement) for the bowl form that I was going to cast.
In the end, I eyeballed and made plaster slope of 3800 cc water + 4940
gm plaster to made the mould. (I didn't not know the resultant volume
of this mixture) I want to learn to do calculations for it so that I
can make estimation ahead of time.
Thanks you in advance for your input
May
Brooklyn NY
--
http://twitter.com/MayLuk
http://www.takemehomeware.com/
May Luk on mon 10 jan 11
Hello all;
I was trying to be a smarty pants and calculate the volume of a
cylinder to figure out how much plaster to pour for a mould.
I have radius =3D 14 cm. Pi =3D 3.14 Height =3D 15 cm.
14 x 14 x 3.14 x 15 =3D 9231
Is that ml / cc for the volume unit?
N.B. This is only for the cylinder, I did not factor in the hollow
part (displacement) for the bowl form that I was going to cast.
In the end, I eyeballed and made plaster slope of 3800 cc water + 4940
gm plaster to made the mould. (I didn't not know the resultant volume
of this mixture) I want to learn to do calculations for it so that I
can make estimation ahead of time.
Thanks you in advance for your input
May
Brooklyn NY
--
http://twitter.com/MayLuk
http://www.takemehomeware.com/
Luke Nealey on mon 10 jan 11
May,
A cubic centimeter is one milli liter. You could figure plaster volume if
you calculate inside volume and then outside volume and subtract.
Luke Nealey
May Luk on mon 10 jan 11
Thanks Luke;
I found out "cm cube" is just plain "cc" or "ml"
http://en.wikipedia.org/wiki/Cubic_centimetre
Question #2: Any body know the formula to get the volume yield of 100
cc water + 130 gm plaster?
May
Thanks also to Lee who sent me this:
http://easycalculation.com/unit-conversion/volume-unit-converter.php
On Mon, Jan 10, 2011 at 1:15 PM, Luke Nealey wrote:
> =3DA0May,
>
> A cubic centimeter is one milli liter. =3DA0You could figure plaster volu=
me=3D
if
> you calculate inside volume and then outside volume and subtract.
>
> Luke Nealey
>
--=3D20
http://twitter.com/MayLuk
http://www.takemehomeware.com/
John Rodgers on tue 11 jan 11
May,
Many times I pour for shapes whose volume is very difficult to measure
because of all the varying shapes in the void. One way I deal with it
is to fill the void with dried grits or beans. Then I pour the grits
into a cylinder so I can get a measure of the volume and I work from
there. Any cheap pellet type medium can be used. The finer the medium
the closer the measurement. Just brush out the void completely before
you set up to pour plaster. Obviously a stray grit particle or bean
could mess things up.
John
John Rodgers
Clayartist and Moldmaker
88'GL VW Bus Driver
Chelsea, AL
Http://www.moldhaus.com
On 1/10/2011 11:05 AM, May Luk wrote:
> Hello all;
>
> I was trying to be a smarty pants and calculate the volume of a
> cylinder to figure out how much plaster to pour for a mould.
>
> I have radius =3D 14 cm. Pi =3D 3.14 Height =3D 15 cm.
> 14 x 14 x 3.14 x 15 =3D 9231
>
> Is that ml / cc for the volume unit?
>
> N.B. This is only for the cylinder, I did not factor in the hollow
> part (displacement) for the bowl form that I was going to cast.
>
> In the end, I eyeballed and made plaster slope of 3800 cc water + 4940
> gm plaster to made the mould. (I didn't not know the resultant volume
> of this mixture) I want to learn to do calculations for it so that I
> can make estimation ahead of time.
>
> Thanks you in advance for your input
>
> May
> Brooklyn NY
>
>
> --
> http://twitter.com/MayLuk
> http://www.takemehomeware.com/
>
>
James Freeman on tue 11 jan 11
On Mon, Jan 10, 2011 at 12:05 PM, May Luk wrote:
Hello all;
I was trying to be a smarty pants and calculate the volume of a
cylinder to figure out how much plaster to pour for a mould.
I am thinking about having my kid write a javascript plaster calculator tha=
t
I could load on a page of my website, so that anyone could run their
calculations free of charge. It will be a good test to see what value I am
getting for all of the money I am shelling out for his computer science
degree! In order to make the program useful. I would appreciate ideas and
input as to what you folks would like to be able to do. I want to keep it
simple, but also make sure it is useful. Here is what I am thinking:
Enter the dimensions of the general shape you are trying to fill, box,
cylinder, and perhaps sphere, in inches or centimeters
(Question: Is it ok to require decimal inches, or should I allow fractiona=
l
inches?)
Enter the desired plaster ratio (default to 70%)
Program would return required dry plaster in both pounds/ounces US and in
grams, and required water in pounds/ounces, grams/milliliters, and standard
US volume measures (gallons, cups, quarts, ounces, etc.)
I am thinking making no allowance for the displaced volume of the model,
allowing this to be the "spare" plaster to make certain you have enough to
fill the mold.
What do you folks think? Does this sound right? Am i missing anything
important? Is this overkill? Also, would folks be interested in a
downloadable smartphone app for Blackberries, Androids, and Apple Ipod
phones? While the envisioned online calculator would be entirely free of
charge, the app would probably have to cost a couple of bucks in order to
make it worth the kids' while to code it (they would get the $, not me).
Let me know your thoughts. If there is interest, I will try to get to work
on it in the next week or so. And yes, I am aware that USG has, or had, a
cardboard sliderule calculator available, but is seems that an online and
smartphone application would be far more useful and convenient.
All the best.
...James
James Freeman
"...outsider artists, caught in the bog of their own consciousness, too
preciously idiosyncratic to be taken seriously."
"All I say is by way of discourse, and nothing by way of advice. I should
not speak so boldly if it were my due to be believed."
-Michel de Montaigne
http://www.jamesfreemanstudio.com
http://www.flickr.com/photos/jamesfreemanstudio/
http://www.jamesfreemanstudio.com/resources
<#>
<#>
<#> <#>
May Luk on tue 11 jan 11
Hello James;
Sounds like a good idea. I personally would not use it. I like to do
maths whenever I can in the studio. It's for my use-it-or-lose-it
brain, not for anything else. Doing maths long hand is relaxing, but I
don't do it enough and I always have doubts about my results.
I have my husband's phone number on speed dial. I won't be able to
reach him if I lose my phone. I hate the thought. I think I am going
to try to memorize some phone numbers for my New Years resolutions.
Best regards
May
On Tue, Jan 11, 2011 at 10:33 AM, James Freeman
wrote:
>
> I am thinking about having my kid write a javascript plaster calculator t=
=3D
hat
> I could load on a page of my website, so that anyone could run their
> calculations free of charge. =3DA0It will be a good test to see what valu=
e =3D
I am
> getting for all of the money I am shelling out for his computer science
> degree! =3DA0In order to make the program useful. I would appreciate idea=
s =3D
and
> input as to what you folks would like to be able to do. =3DA0I want to ke=
ep=3D
it
> simple, but also make sure it is useful. =3DA0Here is what I am thinking:
>
> Enter the dimensions of the general shape you are trying to fill, box,
> cylinder, and perhaps sphere, in inches or centimeters
> (Question: =3DA0Is it ok to require decimal inches, or should I allow fra=
ct=3D
ional
> inches?)
>
> Enter the desired plaster ratio (default to 70%)
>
> Program would return required dry plaster in both pounds/ounces US and in
> grams, and required water in pounds/ounces, grams/milliliters, and standa=
=3D
rd
> US volume measures (gallons, cups, quarts, ounces, etc.)
>
> I am thinking making no allowance for the displaced volume of the model,
> allowing this to be the "spare" plaster to make certain you have enough t=
=3D
o
> fill the mold.
>
> What do you folks think? =3DA0Does this sound right? =3DA0Am i missing an=
ythi=3D
ng
> important? =3DA0Is this overkill? =3DA0Also, would folks be interested in=
a
> downloadable smartphone app for Blackberries, Androids, and Apple Ipod
> phones? =3DA0While the envisioned online calculator would be entirely fre=
e =3D
of
> charge, the app would probably have to cost a couple of bucks in order to
> make it worth the kids' while to code it (they would get the $, not me).
>
> Let me know your thoughts. =3DA0If there is interest, I will try to get t=
o =3D
work
> on it in the next week or so. =3DA0And yes, I am aware that USG has, or h=
ad=3D
, a
> cardboard sliderule calculator available, but is seems that an online and
> smartphone application would be far more useful and convenient.
>
--=3D20
http://twitter.com/MayLuk
http://www.takemehomeware.com/
Randall Moody on tue 11 jan 11
USG used to have a plaster slide rule available. They have a handbook
available online at
http://www.usg.com/resource-center/gypsum-construction-handbook.html I
think that chapter 7 covers conventional plaster.
--
Randall in Atlanta
http://wrandallmoody.com
John Rodgers on wed 12 jan 11
James,
I love my USG slide rule - but it could be more easily decipherable. Re:
your javascript project - go for it! It would be a nice tool for plaster
work.
John
John Rodgers
Clayartist and Moldmaker
88'GL VW Bus Driver
Chelsea, AL
Http://www.moldhaus.com
On 1/11/2011 9:33 AM, James Freeman wrote:
> I am aware that USG has, or had, a
> cardboard sliderule calculator available,
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